A human resources expert on Monday said employers should not face a significant financial burden under a new rule that entitles more workers to benefits such as paid leave and sick and long-service pay.

For the past three and a half decades, workers were eligible to these benefits only if they worked at least 18 hours per week for four consecutive weeks, a requirement known as the “418 rule”.

Eligibility will no longer be determined in this way under the new “468 rule”, which took effect on Sunday.

Instead, workers will qualify for fringe benefits if they accumulate 68 working hours over a four-week period.

According to government estimates, about 11,000 part-time and casual workers will benefit from the new rule.

Roy Ying, co-chair of the advocacy and policy research committee at the Hong Kong Institute of Human Resource Management, said the additional operational costs would be minimal.

“In terms of the additional costs, some industry experts have estimated that if you start paying these fringe benefits, it's going to be about six percent more per person in terms of the overall expenses,” he told RTHK.

“Now, is it too much? If you're looking at about 11,000 workers, that's not a lot of money for the whole workforce. So I believe the impact is not that significant.”

Some companies, Ying said, would probably hire even more people and roster them to work less than 68 hours a month to work around the new rule.

“That means more part-time job opportunities will become available. This is the dynamics of this new change, but I do believe it is also in line with the gig economy trend that we're seeing," he said.

"More and more people are looking for flexibility, and I do believe that some people actually prefer working part-time without having to be stuck with one single employer.”

However, the vice chairwoman of the Federation of Hong Kong and Kowloon Labour Unions, Tam Kam-lin, has called on employers to retain experienced part-time workers.

She said small and medium-sized companies could face extra operating costs if they attempted to work around the new rule by hiring more part-time staff.

“These aren’t large companies, and they still need to train the right people," Tam said.

"The more service oriented a business is – such as explaining products and services to customers – the more important staff quality becomes. Productivity also varies from person to person.

“We think employers should keep experienced staff and offer paid leave, instead of constantly training new hires with unknown capabilities.”

An employer representative of the Labour Advisory Board, Ricky Chan from the Federation of Hong Kong Industries, said the new rule would have a bigger impact on industries with a higher proportion of part-time workers, such as the retail, catering, manufacturing and logistics sectors.

He called on employers to become fully acquainted with the new rule to avoid committing any violations.